Machine for the manufacture of wire tacks



y 12, 1955 H. STUTZER ETAL MACHINE FOR THE MANUFACTURE OF WIRE TACKS Filed July 10 1950 F19. 3 Fig.

127, v ezvors JEZ. 6151175261 Mifiztiar United States PatentO MACHINE FOR THE MANUFACTURE O WIRE TACKS' Hans Stutzer, Koln-Bickendorf, Wilhelm Wattler, Koln- Zollstock, and Matthias Hermann, Koln-Raderberg, Germany Application July 10, 1950, Serial No. 172,866

Claims priority, application Germany July 25, 1949 6 Claims. c1. 10-49 The machines hitherto used for the manufacture of wire tacks work relatively slowly. This arises both from their method of operation and their constructional layout.

As regards their method of operation the wire feed during the individual stages of reduction for shaping the shank is effected by the wire being seized afresh and u fed forward both for the main feed step and also for each individual secondary feed step.

As regards constructional lay-out the known machines are provided with only a single control shaft. This carries various cams which, through lateral rises or swells and levers, actuate the die slide for upsetting the head, the knife slide, the two feed slides for the main feed of the Wire, and for the secondary feed steps during reduction, and finally the reducing lever for the reducing dies in which if necessary the wire is at the same time held fixed during upsetting of the head.

The output of these machines is limited by the fact that the numerous parts have relatively large mass and in particular that the arrangement for the feeding of the wire, on account of its inertia and the exclusively positive engagement between the individual parts, is ill-adapted for carrying out the secondary feed steps of the wire for the second and further reductions since this feed arrangement has to be moved forwardand backward at each separate feed step. The employment ofxa plurality of reductions and therefore short secondary feed steps of the wire cannot be avoided, because with only a single reduction the pressure would be higher and the pressing jaws wider than desirable, and in each case would have to be made equal to the exact lengthof the tack to be made. As a result the wire would .be pressedout too long and too thin, particularly 'at the rear where the reduction of the shank is greatest. The pressed-outmaterialcould not, however, be used for making the nexti'tack-head', because the .too long .and' too thin end would bendover and the .head wouldbe formed to one side ongthe shank. When a plurality of reduction stepsis effected-the pressedout end is only very short and after each reduction is again .thrust' between the pressing jaws-so-that the head is pressed on the full'wire diameter and isround and central. Further, in these known machines the upsetting of the head and the cutting off of the finished article, as already mentioned, is exclusively positively controlled, which with the generally long strokes ofthe parts of the mechanism affects the output capacity of the machine. Finally, the roller of the reducing lever; runs on a lateral cam rise sothat the roller is greatly limited in its diameter ice It will be obvious that the use of this method on the known machines and alteration of the known construction solely in this respect will make possible a substantial increase in output because the accelerations of mass, even with positive engagement of the parts transmitting motion, can be easily effected and only the single return stroke has to be carried out under the action of a spring.

But according to the invention the machine is also adapted in its construction on the one hand to the new method of operation and on the other in other respects; in particular the machine is constructed as a three-shaft machine, the side shafts being driven from the main shaft through equal ratio bevel wheels so that all three shafts rotate in unison. Such three-shaft machines are already known in the case of wire pin machines. But these, in contradistinction to wire tack machines, work without shank reduction so that the problems with which the invention deals do not arise in them.

The forward feed of the wire according to the invention is efiected from one of these side shafts through a feed cam having an adjustable rise or swell for each feed step and always in a forward direction without release of the wire, through a single, light double arm lever, while the reducing lever is arranged at to its usual position and now coacts with a cam disc having a plurality of radially inset and adjustable rises or swells, so that its roller can now be made of large diameter, and hotrunning due to further increase of pressure is avoided.

Even though the output of the machine is substantially increased by these arrangements, to increase it still further positive operation of the heading die slide and the cutoff slide for example through an eccentric (by which term I include a crank) and connecting rod is employed in conjunction with the three shafts.

Corresponding with the constructional features of the invention, the main shaft is in the form of a crank shaft, and carries means for receiving the drive, the connecting rod for the heading die slide and two toothed bevel wheels for transmitting rotation to the two side shafts, of which one carries the knife eccentric and the reducing cam with the adjustable rises or swells as well as a cam for the delivery device, while to the other are secured the other knife eccentric and the feed cam with its rises or swells for the main feed and after-feeds of the wire.

The machine must also have a pincer slide for the' feed of the wire, which is provided with a gripper member which is retracted by a spring and thereby atthe same time holds the feed-in lever against the feed cam. Further, the gripper member positively moved longitudinally by the feed-in lever, may have a special form in that ithas a piston-like extension which engages, and is longitudinally slidable in, a cylindrical holder. The stroke of the gripper may be limited by an adjusting screw projecting into the cylindrical holder and if it is made a substantially air-tight fit its movement may be damped by an air vent from the bore in the holder. In this way trouble free running of the machine is obtained.

.The increase in output capacity of such a machine is so great that it amounts to about eighty per cent of the output hitherto obtained. For this reason the same machines can also be used to manufacture wire pins if the parts used for reduction are put out of action. Such conversion of a Wire tack machine into a wire pin machine was not possible hitherto, because working with a tack machine was uneconomical. Through the increase in output this impediment disappears. The advantage of this possibility is that machine plant of a factory can be substantially reduced since production can be changed over as desired. It is thus immediately possible, in the absence of orders for wire tacks, to use the wire tack machines for increased production of wire pins and thus to reduce the machine plant in respect of wire pin mai chines, as well as to build machines for both purposes operating in accordance with the new method, and thus to effect substantial savings.

An example of wire tack machine in accordance with the present invention is illustrated in the accompanying drawings. 1

Fig. l is a plan view of the machine.

Fig. 2 is a detail of Fig. 1.

Fig. 3 is a face view of the feed cam.

Fig. 4 is a side view of Fig. 3.

Fig. 5 is a development of the lateral rises or swells of the feed cam of Fig. 3.

Fig. 6 is a side view of the reduction cam, and

Fig. 7 is an edge view of Fig. 6.

According to Fig. l the machine is provided with three shafts. The main shaft 14] carries at one end, for example a fixed pulley 11 and a loose pulley 12, as well as a hand wheel 13 for setting the machine. The side shafts 16 and 17 are driven through two pairs of bevel wheels 14 and 15. The two shafts carry eccentrics 13 and 19 by which the knife slides 22 and 23 are actuated through connecting rods 2% and 21. The main shaft is provided with a crank 24, and through a connecting rod 25 operates the heading-die slide 26 for upsetting the head of the tack. On the shaft 15 is a reduction cam 27 with inset adjustable swells 28 and 29 having lug portions 50 and 51 for attachment to the cam by studs 52 and 53 (see Figs. 6 and 7) for effecting the various stages of reduction. On the shaft 17 is secured a cam disc 30 which is provided with the swells 31, 32, 33 and 34 (Figs. 3 to 5), and serves for the wire feed. Swells 31 and 32 are provided with slotted portions 54 and 55 to receive clamping studs 56 and 57 which threadedly engage the cam to permit lateral adjustmentof the swells. The swells work upon a two armed lever 35 pivotedat 3.7, which bears against them with a roller 36. The roller 36 can be made greater in diameter than was possible hitherto because a change in the direction of the swells only occurs at one place, whereas elsewhere the swells always rise in the same direction. At this point also therefore, as previously pointed out with regard to the reduction cam, a decrease in heat development is achieved and the security of the machine is increased by this measure. The other end of the lever serves for longitudinally moving the gripper member 33 which is adapted .1

for one-way engagement with wire stock (not shown) to be fed into the machine toward the left, as viewed in Figure l, which has a piston-like extension 39 moving respectively, in combination therewith means for reducing in a cylindrical bore 4!) shown dotted. in Fig. '2' in a corresponding holder member 48. The strokeof the feed mechanism 38 is limited by an adjusting screw 41 and damping of the movement in the cylindrical bore is effected by an air vent 42. The gripper member, as Fig. 1 shows, is pushed forward (toward the left) against a spring 43, which at the same time presses the double lever 35 against the swells of the feed cam 30. The adjusting screw 41, by limiting the return stroke of the gripper member 38, therefore serves to produce ditierences in the shaft length of the tack by changing the stroke, the swells 31, 32, being adjusted to suit. Greater changes in the main'feed movement areeffected by adjusting the swell 33 about a pivotal connection 46 by means of a screw 49 provided on the cam 30, or changing it for another of greater or less height. Use can be made of a set of calibrated swell pieces which simply need to be exchanged. The swells 31, 32, then have to be suited to the leading end 44 of the calibrated piece 33. The calibrated piece 33 has the same run-ofi part. 45 for all rises. During its adjustment the calibrated piece 33 can be swungrabout its pivotal axis 46. In place of the adjusting screw 41 which serves as a stop for limiting the stroke of the gripper member 38, a corresponding abutment 47 can be provided on the feed cam 30, or some similar stop. I

the shank of a tack, a reducing cam on one of said side shafts for operating said shank reducing means several times during the production of a single tack, a gripper member for feeding the wire stock, a feed cam'on the other of said side. shafts, transmission means between said gripper member and said feed cam, said feed cam having a sequence of successively'rising swells adapted through the intermediary of said transmission means to move said gripper member in the feeding direction in a sequence of steps asynchronous to the operation of said reducing means during the production of a single tack, and also having a run off portion following upon the sequence of successively rising swells to allow said gripper toreturn into its initial position.

2. Machine for the manufacture of wire tacks as set forth in claim 1, wherein the transmission means between the gripper member and-the feed cam consists of a rocker lever one extremityof which engages the gripper member whereas its other extremity carries a roller maintained in contact with the working surface of the feed camby a spring which constitutes the means for assisting the return of said gripper member into its initial position.

3. In a machine for the manufacture of wire tacks as set forth in claim 1, means for damping the movement of said gripper member comprising a piston-like extension on the gripper member, and a holding member having a cylindrical bore accommodating said piston-like extension to cushion the return movement of the gripper member, and means for limiting the return movement of the gripper member and thus determining the length of wire-stock fed by said'grippermember.

4. In a machine forthe manufacture of wire tacks as set forth in claim 1, means for adjusting the height of the individual rising swells on the feed cam to determine each step of the progressive feed movements of the gripper under the action of the successively rising swells on the feed. cam.

- '5. In amachine for the manufacture of wire tacks as set forth inclaim 1, means for damping the movement of said gripper member comprising a piston-like extension on the. gripper member, and a holding member having a cylindrical bore accommodating said piston-like extension to cushion the return movement of the gripper member, and a screw adjustable in said holder member to limit the return movement of the gripper member and thus determine the length of wire fed by said gripper member.

6. In a machine for the manufacture of wire. tacks as set forth in claim 1, means for damping the movement of said gripper member comprising a piston-like extension on the gripper member, and a holding member hav ing a cylindrical bore accommodating said piston-like extension and an air vent extending from the cylindrical bore to allow the gradual escapement of air from said bore under the action-of the piston-like extension during the return movement of the gripper member.

References Cited in the file of this patent UNITED STATES PATENTS 

